The present invention relates to a program of events, ingredients, controls, and sensors that make it possible to produce a laundering machine that is self-contained, automatic, and relatively compact. It can be used in the home, lightly in industry as well as commercially, and is capable of utilizing a complete aqueous cycle, a semi-aqueous cycle, or a non-aqueous cycle. Additionally, the present invention describes a method of drying fabric that contains water and a soil. The machine offers the consumer the ability not only to launder their traditional fabrics (cotton, polyesters, etc.) at home, but also have the ability to handle delicate fabrics such as dry-clean only fabrics, nano-coated fabrics, and fabrics that contain electronics as well.
Water, as a cleaning solvent itself, has many benefits as well as disadvantages. Water is useful as a cleaning agent for many soils especially hydrophilic soils and provides excellent solubility characteristics with conventional detergent formulations. However, water is responsible for damage (shrinkage and wrinkling) to many of the traditional garments laundered at home. Additionally, water is very polar causing it to hydrogen bond readily, has a high heat capacity, and a low vapor pressure making it difficult to remove from fabric without adding a lot of energy either in terms of heat or centrifugation.
On the contrary to aqueous-based cleaning, there have been numerous attempts at making a non-aqueous laundering system; however, there have been many limitations associated with such attempts. Traditional dry-cleaning solvents such as perchloroethylene are not feasible for in-home applications because they suffer from the disadvantage of having perceived environmental and health risks. Fluorinated solvents such as hydrofluoroethers have been proposed as potential solvents for such an application. These solvents are environmentally friendly, have high vapor pressures leading to fast drying times, and provide some level of cleaning, but have some limitations with hydrophilic stain removal.
Other solvents have been listed as potential fluids for such an application. Siloxane-based materials, glycol ethers, and hydrocarbon-based solvents all have been investigated. Typically, these solvents are combustible fluids but the art teaches some level of soil removal. However, since these solvents are combustible and usually have low vapor pressures, it would be difficult to dry with traditional convection heating systems. The solvents have low vapor pressures making evaporation slow; thus increasing the drying time needed for such systems. Currently, the National Fire Protection Association has product codes associated for flammable solvents. These safety codes limit the potential heat such solvents could see or the infrastructure needed to operate the machine. In traditional washer/dryer combination machines, the capacity or load size is limited based on the drying rate. However, with the present invention, the capacity of the machines will be more dependent upon the size of the drum than the size of the load.
The present invention uses some of these aforementioned solvents to clean fabrics without the drying problems associated with these solvents. This is accomplished by using a non-flammable, non-aqueous working fluid that solves many of these drying problems. This system incorporates a process wherein water or other polar solvents could be used as cleaning fluids and traditional means for removing the aqueous solvent from the fabric such as convection based drying methods could be utilized. This present invention also allows for a non-aqueous drying means for these aqueous cleaning solvents. Additionally aqueous and non-aqueous solvents can be combined giving the consumer the semi-aqueous option of cleaning with an aqueous solvent for superior hydrophilic soil removal, cleaning with a non-aqueous fluid for superior hydrophobic soil removal, and then drying with one or more non-aqueous fluids to provide reasonable drying/cycle times. Further the consumer can select a complete non-aqueous cycle wherein a non-aqueous fluid cleans the fabric and the same or an additional non-aqueous fluid is used for drying.
U.S. Pat. No. 5,498,266 describes a method using petroleum-based solvent vapors wherein perfluorocarbon vapors are admixed with petroleum solvent vapors to remove the solvents from the fabrics and provide improvements in safety by reducing the likelihood of ignition or explosion of the vapors. However, the long-term stability of these mixtures is unknown but has the potential of separating due to dissociating the separate components.
U.S. Pat. No. 6,045,588 describes a method for washing, drying and recovering using an inert working fluid. Additionally, this application teaches the use of liquid extraction with an inert working fluid along with washing and drying.
U.S. Pat. No. 6,558,432 describes the use of a pressurized fluid solvent such as carbon dioxide to avoid the drying issues. In accordance with these methods, pressures of about 500 to 1000 psi are required. These conditions would result in larger machines than need be for such an operation. Additionally, this is an immersion process that may require more than one rinse so additional storage capacity is needed.
U.S. Patent Publication Number 20030084588 describes the use of a high vapor pressure, above 3-mm Hg, co-solvent that is subjected to lipophilic fluid containing fabric articles. While a high vapor pressure solvent may be preferred in such a system, US 20030084588 fails to disclose potential methods of applying the fluid, when the fluid should be used, methods minimizing the amount of fluid needed as well as potential use of aqueous fluids as well.
Various perfluorocarbons materials have been employed alone or in combination with cleaning additives for washing printed circuit boards and other electrical substrates, as described for example in U.S. Pat. No. 5,503,681. Spray cleaning of rigid substrates is very different from laundering soft fabric loads. Moreover, cleaning of electrical substrates is performed in high technology manufacturing facilities employing a multi-stage that is not readily adaptable to such a cleaning application.
U.S. Pat. No. 5,888,250 describes a biodegradable ether solvent which may be used as a dry cleaning solvent or as a solvent for completing non-aqueous cleaning in the home.
US Patent Publication Number 20030046963 is a patent application disclosing a machine that can be preprogrammed to use a selective amount of water for laundering fabrics.
WO 0194675 describes the use of an apparatus capable of aqueous and non-aqueous methods for laundering. This application fails to teach any embodiments in which these methods can be easily practiced. Additionally, the solvent choices readily identified by this application, decamethylcyclopentasiloxane and water, are readily incompatible and for such a machine or method to work the apparatus would need to be equipped with separate hosing or involve a clean-out cycle between runs utilizing a solvent or water. This application differs from the present invention in that the present invention describes an additional semi-aqueous method plus describes methods in detail on how to minimize the cycle times for both aqueous and non-aqueous-based cleaning fluids.
US Patent Publication Number 20030196277 describes figures wherein an apparatus is capable of completing both a solvent-based cleaning and water washing process. This application fails to teach any embodiments wherein the aforementioned processes can be completed. The present invention not only discloses and teaches methods, chemistries, and apparatus wherein a non-aqueous and aqueous cleaning cycle are possible, but methods for minimizing solvent usage as well as processes for minimizing cycle time.
The disclosures and drawings of each of the above references are incorporated herein by reference.
An object of the present invention is to provide a complete sequence of laundering wherein the system can utilize an aqueous process, a semi-aqueous process, or a non-aqueous process while drying quickly.
A further object of the invention is the provision of a specific process wherein an aqueous wash is followed by a non-aqueous rinse to improve the cycle time by reducing the time needed to dry.
Another object of the invention is the provision of techniques and methods for minimizing the amount of non-aqueous fluid needed and the time that the non-aqueous fluid should be in contact with the fabric articles.
Another object of the invention is the provision of a low energy drying process that results in improved fabric care and shorter drying times.
Another object of the invention is the provision of recovery methods and techniques for the semi-aqueous and non-aqueous systems described in this invention.
A further object of the invention is the provision of a single apparatus with multiple working fluid options including water wherein the apparatus is designed to complete either an aqueous, semi-aqueous, or non-aqueous laundering methods, low temperature drying, and recovery methods.
A further object of the invention is the provision of means for concentrating and disposing of soils in an environmentally friendly manner.
It is a further object that the materials used are all of a type that avoids explosion and manages flammability hazards.
Another object of the present invention is the provision of means wherein the drying always occurs in the presence of a non-flammable fluid rich environment.
It is still a further object of the present invention that the consumer can select an aqueous cleaning cycle and a non-aqueous fast drying cycle.
Another object of the present invention is the provision of means whereby the consumer can select a non-aqueous fast drying cycle with a traditional hand/feel wherein moisture is added at the end of the cycle.
It is still a further object of the present invention to provide specific chemistries and materials that make the aqueous, semi-aqueous, and non-aqueous processes of the present invention possible.
Further objects and advantages of the invention will become apparent to those skilled in the art to which this invention relates from the following description of the drawings and preferred embodiments that follow: